But the S&P 500 reaching 2,000 would be a more significant event, market strategists say.

"Nobody gets measured against the Dow; you follow the money, and the S&P 500 is the benchmark. It's up over 7 percent, and a lot of money managers aren't. So people look at their portfolios and wonder why. It puts pressure on those money managers who are under invested," said JJ Kinahan, chief strategist at TD Ameritrade.

And, while the Dow and S&P are in uncharted terrain, the Dow's year-to-date gain is under 3 percent, lagging both the S&P 500 and the Nasdaq Composite, with the technology-heavy index also up more than 7 percent for 2014.

"The next leg up in stocks is the 2,000 mark on the S&P," Kinahan added.

"We typically keep our eyes more focused on the S&P," said David Lyon, a global investment specialist at JP Morgan Private Bank in San Francisco.

"With all equity markets hitting all-time highs, valuations are reasonable to getting stretched. Rather than specific psychological barriers, the S&P is absolutely on track for a very good year," said Lyon, who projects the index will rise between 8 to 12 percent in 2014.